Thyme Oil Research Articles

An essential oil blend of citronella, red thyme, and clove bud kills common hydroponic pests and pathogens

Protected cropping utilizing hydroponic systems are particularly vulnerable to the impacts of waterborne diseases which result in substantial crop damage and yield loss. This study assessed the potential of a citronella, red thyme, and clove bud essential oil blend (EOB) for plant safety, and pesticidal and antimicrobial activities. Results within model systems identified efficacy of EOB against aphids (p < 0.001), spider mites (p < 0.001), and fungus gnats (p < 0.001), and 250-fold diluted EOB against Pythium (p < 0.001), Phytophthora (p = 0.001), and Fusarium (p < 0.001). The plant safety trial indicated no impacts of 250-fold diluted EOB to capsicum health and glasshouse experiments demonstrated both curative and preventative efficacies against Pythium, based on reductions in the incidence and severity of infection. These results highlight the potential for the utilization of biopesticides for the effective and environmentally friendly management of common pests and diseases within hydroponic crop systems.

Essential oils of thyme (Thymus vulgaris) and oregano (Origanum vulgare) as an alternative for the control of pesticide-resistant Fusarium spp. in quinoa seeds.

The phytopathogenic genus Fusarium can cause damage such as root and stem rot in economically important crops, with significant implications. To seek a sustainable method for controlling this phytopathogen in seeds, the antifungal activity of essential oils (EOs) from thyme (Thymus vulgaris) and oregano (Origanum vulgare) was evaluated against isolates of F. graminearum, F. equiseti, F. culmorum and F. oxysporum originating from quinoa (Chenopodium quinoa) crops in the Boyacá (Colombia). Initially, the effectiveness of commercial fungicides against the mentioned phytopathogenic fungi was evaluated. Upon verifying that these isolates exhibited high resistance to these compounds, the EOs were assessed as a potential control alternative. A disk diffusion assay demonstrated complete in vitro inhibition of the growth of the evaluated phytopathogens when undiluted EOs were used. Subsequently, the minimum inhibitory concentration (MIC) of these oils was determined using the agar well diffusion technique, revealing a MIC of 10 and 1 μL mL-1 for thyme and oregano oil, respectively. Following this, the antifungal activity of the EOs applied to quinoa seeds was evaluated, and germination indices were measured as an indirect indicator of their toxicity. Despite both EOs successfully inhibiting microbial growth in the seeds, it was also found that thyme EO at 100 μL mL-1 and oregano EO at 10 μL mL-1 inhibited seed emergence and germination. However, lower concentrations exhibited a reduction in fungal population without affecting these germination indices. Therefore, it is suggested that the use of these compounds has potential in the treatment and disinfection of quinoa seeds. © 2024 Society of Chemical Industry.

Antioxidant Capacity of Thyme (Thymus vulgaris) Essential Oil and Its Effect on In Vivo Fertility of Rams Subjected to Testicle Heat Stress.

The detrimental effects of hyperthermia on the testes and the protective effect of thyme essential oil against testicular damage induced by this stress in rams were studied. Twenty-four rams of the Barbarine breed with an average weight of 62.5 ± 0.3 kg and an average age of 24 ± 0.6 months. The experiment consisted of inducing localized heat stress on the first group of rams by applying heat bags to both testicles of six rams (G s). The second group underwent the same heat stress on the testes but received orally 100 µL/day/animal of thyme essential oil (G s-he). A positive control did not undergo stress but received thyme essential oil (G he) with the same doses as the (G s-he) group, and the negative control did not undergo either stress or receive the essential oil of thyme (G c). One hundred twenty-eight adult ewes of the same breed divided into four groups of 32 ewes were used to study the effect of different treatments on the in vivo ram's fertility. Ewes are synchronized and we have applied natural mating with oestrus control, the reproduction balance sheet is calculated after lambing. The results showed that tests of heat stress (HS) negatively affect semen quality but did not cause infertility. However, neither tests for heat stress nor treatment with thyme EO significantly affected the haematological profile. The study of the effect of heat stress on the testes on fertility in vivo showed a drop in the number of females who were fertilized at the first oestrus and consequently a drop in fertility. However, the rams that suffered the same stress but were treated with EO thymus recorded an improvement in these parameters.

Optimization of antimicrobial properties of essential oils under rotating magnetic field

Essential oils (EOs) extracted from Thymus vulgaris L. (TEO) and Rosmarinus officinalis L. (REO) have aroused interest in their application to food preservation or in alternative medicine or aroma-therapy. In this study, the chemical compositions of essential oils were determined and analyzed. The purpose of the investigation was to investigate in detail the activity of essential oils extracted from herbs (thyme and rosemary) and exposed to rotating magnetic filed (RMF) against the model Gram-negative bacteria Escherichia coli The bacterial removal has been optimized by a surface response methodology (RSM). It was shown that TEO in a concentration of 10 µL/50 mL of water resulted in a total bacterial number reduction after 40 min under the RMF. Rosemary's antibacterial effect was much weaker. Thus, we summarized that the rotating magnetic fields at a frequency of 27 Hz can increase the antimicrobial efficiency but the effect depends on the type of essential oil. High-rate bacteria removal was obtain for thyme oil in concentration of 30 µL of thyme oil to 50 mL of bacterial suspension, exposed to RMF at a frequency of 27 Hz for 40–60 min.

Antimicrobial Activity of Commercial Essential Oils Available in the Market of Kathmandu

Given the increasing global apprehension surrounding antibiotic resistance, there has been growing interest in exploring natural compounds, specifically essential oils, as potential substitutes for combating microbial pathogens. This research work aimed to evaluate the antimicrobial activity exhibited by commercial essential oils and by diluting them with the carrier oils at equal concentration. The screening of antimicrobial activity was conducted using the agar well diffusion method with eight essential oils. Using the broth dilution method, the antibacterial activity of eight commonly used essential oils: lavender, tea tree, eucalyptus, peppermint, thyme, citrus, rosemary, and cinnamon were assessed. Both Gram-positive and Gram-negative species were selected for antimicrobial activity. The minimum inhibitory concentration (MIC) was determined by the broth dilution method. Following MIC determination, a sub-culture was performed on nutrient agar plates to ascertain the minimum bactericidal concentration (MBC). All the antibiotics used in the study demonstrated sensitivity when subjected to the antibiotic susceptibility test. Thyme, cinnamon and peppermint strongly inhibited the growth of S. epidermidis 46 mm, 30mm, and 34 mm respectively. Findings revealed distinct variations in the MIC values among the different essential oils and bacteria tested. Thyme and tea tree oils exhibited the broadest antibacterial spectrum, inhibiting both Gram-positive and Gram-negative bacteria at relatively low concentrations. Thyme (15.625 μl/ml) and tea tree (31.25 μl/ml) oil demonstrated promising activity against Gram-positive pathogen, while tea tree oil (15.625 μl/ml) displayed better efficacy against Gram-negative bacteria. A significant outcome was observed when the essential oils were diluted with carrier oils, indicating promising results in terms of antibacterial activity. These findings highlight the potential of essential oils, particularly thyme and tea tree oils, as effective natural antimicrobial agents.

Optimization of dolutegravir and Epigallocatechin gallate loaded nanoemulsion for enhanced oral delivery in NeuroAIDS management

The present study aimed to develop a nanoemulsion loaded with dolutegravir (DTG) and Epigallocatechin Gallate (EGCG) to achieve a combined and synergistic effect for improved oral delivery, facilitating more effective management of NeuroAIDS. Thyme oil was chosen as the oil, tween 80 as the surfactant, and transcutol®HP as the co-surfactant following extensive screening of experiments. The nanoemulsion was fabricated using the ultrasonication technique and optimization was performed using a Central Composite Rotatable Design (CCRD) to attain the best formulation following parameters like droplet size, polydispersity index (PDI), zeta potential, % transmittance, pH, refractive index, viscosity and conductivity of the optimized nanoemulsion, which were found to be 45.36 nm, 0.2462, −6.226 mV, 96.30 ± 0.20 %, 6.84 ± 0.32, 1.70 ± 0.12, 31.17 ± 0.21 mPas, and 0.217 ± 0.002 mS/cm, respectively. The developed formulation was thoroughly characterized and investigated through various in vitro studies, demonstrating enhanced drug release. The nanoemulsion showcased a spherical and globular nature of the droplets, resulting in improved drug bioavailability compared to the pure drug. In conclusion, the DTG and EGCG-loaded nanoemulsion formulation offers a promising approach for achieving a combined anti-HIV effect, with potential for effective NeuroAIDS management. Future investigations will focus on validating the anti-HIV-1 properties of this nanoemulsion formulation, employing in-depth mechanistic analysis through in vitro preclinical studies, to further elucidate their synergistic effects and optimize therapeutic potential against HIV-1 infection.

Study of the chemical composition of the essential oil derived from Thymus lancéolatus desf, an endemic aromatic plant native from Algeria and evaluation of its efficacy against Paenibacillus larvae and Ascosphaera Apis, two diseases affecting the honeybees, Apis mellifera

The essential oil and hydrolate of Thymus lancéolatus desf, an endemic aromatic plant native to the mountains of northwestern Algeria, were tested in vitro for their antimicrobial activity against the bacteria Paenibacillus larvae, the causative agent of American foulbrood, and the fungi Ascosphaera apis, the responsible agent of chalkbrood disease in honeybees, Apis mellifera. The oil was extracted from various aerial parts of the plant using steam distillation. It shows high efficacy against both diseases, while its hydrolat demonstrates high efficacy against A.apis alone. The lethal doses (LD100) of the fungi were estimated at 0.034% and 25.30% for the essential oil and the hydrolat, respectively. The estimated concentration of the DL100 bacteria was 17.37 ul/Disc of EO. The hydrolate had no effect on P. larvae. This exceptional double efficacy of T.lancéolatus desf EO has been attributed to its particular active compound, Durenol, which constitutes 34.8% of the oil and the high quantities of its precursors (γ-Terpinene (16.71%) and Sylvestrene (15.17%) contribute to its effectiveness. Also, the abcence of acetate compound further enhances its efficacy. EO of Thyme was proven to be the most effective essential oil in vitro against P. larvae and A. apis, making it an excellent natural alternative to antibiotics.

Bio-Pesticidal Potential of Nanostructured Lipid Carriers Loaded with Thyme and Rosemary Essential Oils against Common Ornamental Flower Pests

The encapsulation of essential oils (EOs) in nanostructured lipid carriers (NLCs) represents a modern and sustainable approach within the agrochemical industry. This research evaluated the colloidal properties and insecticidal activity of NLCs loaded with thyme essential oil (TEO-NLC) and rosemary essential oil (REO-NLC) against three common arthropod pests of ornamental flowers: Frankliniella occidentalis, Myzus persicae, and Tetranychus urticae. Gas chromatography–mass spectrometry (GC-MS) analysis identified the major chemical constituents of the EOs, with TEO exhibiting a thymol chemotype and REO exhibiting an α-pinene chemotype. NLCs were prepared using various homogenization techniques, with high shear homogenization (HSH) providing the optimal particle size, size distribution, and surface electrical charge. A factorial design was employed to evaluate the effects of EO concentration, surfactant concentration, and liquid lipid/solid lipid ratio on the physicochemical properties of the nanosuspensions. The final TEO-NLC formulation had a particle size of 347.8 nm, a polydispersity index of 0.182, a zeta potential of −33.8 mV, an encapsulation efficiency of 71.9%, and a loading capacity of 1.18%. The REO-NLC formulation had a particle size of 288.1 nm, a polydispersity index of 0.188, a zeta potential of −34 mV, an encapsulation efficiency of 80.6%, and a loading capacity of 1.40%. Evaluation of contact toxicity on leaf disks showed that TEO-NLC exhibited moderate insecticidal activity against the western flower thrips and mild acaricidal activity against the two-spotted spider mite, while REO-NLC demonstrated limited effects. These findings indicate that TEO-NLCs show potential as biopesticides for controlling specific pests of ornamental flowers, and further optimization of the administration dosage could significantly enhance their effectiveness.

Thyme and Oregano Oil Potential Therapeutics against Malathion Toxicity through Biochemical, Histological, and Cytochrome P450 1A2 Activities in Male Wistar Rats.

The widespread use of malathion may offer several hazards to humans and animals; additionally, many medicinal plants provide what is known as a broad antitoxicity treatment. This study was carried out to investigate hazardous biochemical and histological reactions to MOP and evaluate the effectiveness of TEO and OEO essential oils in restoring normal physiological conditions after MOP exposure by measuring enzyme-specific activity for Cytochrome P450 1A2 (CYP1A2). One hundred and twenty rats were divided into six groups of twenty animals each: (i) C - MOP served as the control group, (ii) C + MOP treated with 5 mg/kg/BW of Malathion-D10, (iii) TEO treated with 100 mg/kg/BW of oregano essential oil, (iv) TEO treated with 100 mg/kg/BW of thyme essential oil, (v) MOP + OEO treated with 5 mg/kg/BW of Malathion-D10 and 100 mg/kg/BW of oregano essential oil, and (vi) MOP + TEO treated with 5 mg/kg/BW of Malathion-D10 and 100 mg/kg/BW of thyme essential oil. The results indicated the protective effects of OEO and TEO against MOP-induced weight loss. Additionally, there was a significant improvement in ALT, AST, and ALK-Ph after being treated with OEO and TEO, either alone or after MOP exposure. Also, treatment with OEO and TEO ameliorated these oxidative stress parameters, indicating their antioxidative properties. A histopathological examination of liver tissues showed reduced hepatocellular damage and improved liver architecture in the OEO and TEO, both alone and in combination with MOP, and protective effects were more pronounced in the TEO-treated groups. However, the results indicated that TEO was more effective than OEO in increasing CYP1A2 expression and alleviating MOP-induced toxicity. Specifically, TEO showed higher protein expression and therapeutic action in reducing liver damage. In conclusion, these findings suggest that OEO and TEO may be potent therapeutic agents against MOP toxicity, offering protective effects by enhancing CYP1A2 activity and mitigating organ damage. Such knowledge would be an important step toward developing potentially unique treatment options for natural antitoxins.

Synergetic effect between Thyme oil and betaine as growth promotor, performance enhancer and growth responsible gene stimulant in broiler chickens

Synergetic effect between Thyme oil and betaine as growth promotor, performance enhancer and growth responsible gene stimulant in broiler chickens

Acute effect of the novel cadaver fixation and storage solution -Anatomical-biomechanical-microbiological study

Cadaver education is a golden standard in health sciences. It is aimed to purify the cadavers from microbes by subjecting them to chemicals and to be used for many years by terminating autolysis. As a result of literature searches, a solution consisting of a mixture of borax, nitrite-nitrate, glycerin, alcohol, and thyme oil was created. While seven sheep hearts were placed in this solution, seven were kept in 10% formaldehyde for two months for fixation and storage. At the end of the first ten days, it was observed that the discoloration of the heart in the solution was lower than the formalin fixation. In histological examinations, it was observed that there was no visual difference between the groups and the tissue could be examined at all magnifications. At the end of two months, insignificant microbial growth observed in the solution. While color changes were better than formaldehyde, texture profile analysis values were found to be closer to fresh heart. In histological examinations, in the solution group, although the tissue could be recognized at all magnifications, it was observed that cell nuclei were less stained at x100. It was concluded that this solution can be used mainly in short-term courses.

Effect of Adding Essential Oils of Nigella sativa and Thyme on the Yogurt Flavor

Effect of Adding Essential Oils of Nigella sativa and Thyme on the Yogurt Flavor

Green Alternatives for the Control of Fungal Diseases in Strawberry: In-Field Optimization of the Use of Elicitors, Botanical Extracts and Essential Oils

Finding safe and reliable alternatives to fungicides is currently one of the biggest challenges in agriculture. In this regard, this experiment investigated the effectiveness of different elicitors, botanical extracts and essential oils to control grey mold (Botrytis cinerea) and powdery mildew (Podosphaera aphanis) on strawberry plants. This trial was conducted in field conditions under a plastic tunnel with strawberry plants ‘Elsanta’. A first group of strawberry plants was treated before flowering with elicitors [acibenzolar-S-Methyl–(BTH), chitosan], botanical extracts (seaweed extract, alfalfa hydrolysate) and essential oils (thyme and juniper), and grey mold incidence on flowers was evaluated (Experiment 1). Furthermore, a second group of plants was treated before (Experiment 2) and after (Experiment 3) controlled inoculation with P. aphanis. The results indicated that the incidence of flower infected by B. cinerea was reduced by approximately 50% with thyme and juniper essential oils’ applications compared to the untreated control, with no significant difference observed compared to the commercial fungicide penconazole (positive control). As a consequence, the final yield of essential-oil-treated plants was +27% higher than that of non-treated plants. No significant differences emerged for other tested products against grey mold. However, gene expression analysis showed an up-regulation (&gt;2 ÷ 5 folds as compared to control 4 days after application) of FaEDS1, FaLOX and PR gene expression (FaPR1, FaPR5, FaPR10) in leaves treated with BTH. The other natural substances tested also induced defense-related genes, albeit at a lower level than BTH. In Experiment 2, all treatments applied prior to inoculation significantly reduced the incidence and severity of powdery mildew as compared to control. At 28 days after inoculation, chitosan and thyme essential oil applications performed similarly to their positive controls (BTH and penconazole, respectively), showing a significant reduction in disease incidence (by −84 and −92%) as compared to control. Post-inoculum application of essential oils (Experiment 3) showed an efficacy similar to that of penconazole against powdery mildew. These results indicated that the tested substances could be used as alternatives to fungicides for the control of grey mold and powdery mildew in strawberry, therefore representing a valuable tool for the control of these fungal diseases under the framework of sustainable agriculture.

Activity of Common Thyme (Thymus vulgaris L.), Greek Oregano (Origanum vulgare L. ssp. hirtum), and Common Oregano (Origanum vulgare L. ssp. vulgare) Essential Oils against Selected Phytopathogens.

The aim of this study was to determine the activity of common thyme (Thymus vulgare L.), Greek oregano (Origanum vulgare L. ssp. hirtum), and common oregano (Origanum vulgare L. ssp. vulgare) essential oils (EOs) against selected phytopathogenic microorganisms in relation to their chemical profile. The EOs were obtained from the herbs of 2-year-old plants cultivated in the organic farming system in a temperate climate in Central Europe. The EOs' composition was determined by GC/MS and GC/FID. The investigated species were represented by the following three chemotypes: 'thymol' for common thyme, 'carvacrol' for Greek oregano, and mixed 'caryophyllene oxide + β-caryophyllene' for common oregano. The antimicrobial activity of the EOs was assessed based on minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values. The plant pathogenic bacteria Pseudomonas syringae, Xanthomonas hortorum, Erwinia carotovora, and fungi: Fusarium culmorum, Alternaria alternata, Botrytis cinerea, Epicoccum purpurascens, Cladosporium cladosporioides, Phoma strasseri, and Pythium debaryanum were tested. The EOs revealed a stronger inhibitory effect against fungal growth in comparison to bacterial growth (MIC: 0.016-2 µL/mL for fungi and 0.125-4 µL/mL for bacteria). Common thyme and Greek oregano EOs indicated stronger antimicrobial power than common oregano EO. These results were associated with the chemical profile of the analysed EOs. The growth of examined bacteria and fungi strains (in particular, X. hortorum, F. culmorum, and P. debaryanum) were negatively correlated with the content of phenolic monoterpenes and monoterpene hydrocarbons. Among the tested strains, P. strasseri turned out to be the most sensitive (MIC 0.016 µL/mL) and E. carotovora the most resistant (MIC 0.250-4 µL/mL) to all investigated EOs.

The Potential of Thymus serpyllum Essential Oil as an Antibacterial Agent against Pseudomonas aeruginosa in the Preservation of Sous Vide Red Deer Meat.

Foodborne infections caused by microbes are a serious health risk. Regarding this, customer preferences for "ready-to-eat" or minimally processed (MP) deer meat are one of the main risk factors. Given the health dangers associated with food, essential oil (EO) is a practical substitute used to decrease pathogenic germs and extend the shelf-life of MP meals. Nonetheless, further data regarding EO use in MP meals are required. In order to evaluate new, safer alternatives to chemicals for disease control and food preservation, this research was carried out in the following areas to assess the antibacterial and antibiofilm characteristics of Thymus serpyllum (TSEO) essential oil, which is extracted from dried flowering stalks. Furthermore, this study applied an essential oil of wild thyme and inoculated the sous vide deer meat with Pseudomonas aeruginosa for seven days at 4 °C in an effort to prolong its shelf-life. Against P. aeruginosa, the essential oil exhibited potent antibacterial action. The findings of the minimal biofilm inhibition concentration (MBIC) crystal violet test demonstrated the substantial antibiofilm activity of the TSEO. The TSEO modified the protein profiles of bacteria on glass and plastic surfaces, according to data from MALDI-TOF MS analysis. Moreover, it was discovered that P. aeruginosa was positively affected by the antibacterial properties of TSEO. The anti-Pseudomonas activity of the TSEO was marginally higher in vacuum-packed sous vide red deer meat samples than in control samples. The most frequently isolated species from sous vide deer meat, if we do not consider the applied bacteria Pseudomonas aeruginosa, were P. fragi, P. lundensis, and P. taetrolens. These results highlight the antibacterial and antibiofilm qualities of TSEO, demonstrating its potential for food preservation and extending the shelf-life of deer meat.

A Straightforward Electrochemical Approach for the Simultaneous Determination of Thymol and Carvacrol in Essential Oils

A novel, simple, rapid, and non-expensive analytical method based on square wave voltammogram at Pt-microelectrode coupled with partial least square multivariate calibration was used for the simultaneous quantitation of thymol (THY) and carvacrol (CAR) in thyme and oregano essential oils. Results demonstrated that the multivariate calibration method successfully exploited the first-order advantage, rendering highly satisfactory quantitative figures (average recoveries not statistically different than 100%). Moreover, the results agree well with those obtained from the official analytical method. Last, the method’s environmental sustainability was asserted using the AGREE metric, highlighting its eco-friendly nature. More importantly, the proposed analytical procedure does not require previous sample preparation or electrode surface modification. The results underscore the suitability of the method for determining THY and CAR in essential oils at low concentrations (LOD ~ 7.6 µM) with REP% below 5.6%, meeting the requirements of the green analytical chemistry.

GC-MS, FTIR analysis and effects of thyme (Thymbra capitata L. Cav) and rosemary (Rosmarinus officinalis L.) essential oils on the growth and pathogenicity of Botrytis fabae

ABSTRACT This study examined the efficacy of rosemary (Rosmarinus officinalis L.) and thyme (Thymbra capitata L. Cav) essential oils (EOs) in Botrytis fabae management. The key compounds identified in thyme EO were carvacrol (48.13%), 4-Methoxystyrene (17.32%), and cyclohexene (12.37%), whereas the rosemary EO contained α-pinene (55.08%), camphene (10.52%), and d-limonene (7.86%). In vitro tests showed that thyme EO was more effective than rosemary, achieving total inhibition of B. fabae at a concentration of 50 µL compared to 250 µL for rosemary EO. Molecular docking indicated that the primary compounds in each EO interacted with 14 alpha-sterol demethylase. Greenhouse tests confirmed that both EOs significantly reduced disease severity without phytotoxicity. These findings suggest that thyme and rosemary EOs could be effective in B. fabae management, thereby promoting eco-friendly agriculture.

Slow-release antimicrobial preservation composite coating based on bamboo-derived xylan–A new way to preserve blueberry freshness

In recent years, the biocompatibility and environmental friendliness of xylan-based materials have demonstrated great potential in the field of food packaging and coatings. In this study, the cationized xylan based composite coating (CXC) was developed using a hybrid system of cationic-modified bamboo xylan (CMX) and sodium alginate (SA) combined with thyme oil microcapsules (TM). The optimized CXC-B was composed of 1.27 % TM, 2.42 % CMX (CMX: SA = 3:2), and 96.31 % distilled water. When applied to the surface of a blueberry, the CXC-B treatment extended the ambient storage time of the fruit to 10 days while substantially reducing its morbidity (P < 0.05) and protecting its texture, flavor, and nutritional integrity. The resulting composite coating provides a promising solution to the problem of blueberry perishability during ambient storage.

Antifungal potential of essential oils from different botanical sources against Penicillium digitatum: chemical composition and antifungal mechanisms of action by direct contact and volatile

Fungal deterioration is a recurring problem in citrus fruits, and the search for natural preservatives has been widely publicised. Therefore, the in vitro antifungal activity of clove, white thyme, tea tree, Eucalyptus citriodora, Eucalyptus staigeriana, green mandarin, sicilian lemon, sweet orange, and bergamot essential oils (EO’s) was evaluated against the mycelial growth of Penicillium digitatum isolated from contaminated citrus fruits, by direct contact and volatiles action. In addition, the chemical composition and volatile compounds of the EO’s were evaluated by gas chromatography. Clove, white thyme, and Eucalyptus citriodora EO’s inhibited 100% of the mycelial growth of P. digitatum by direct contact and volatile action at concentrations ≤ 2 µL/mL. On the other hand, EO’s from citrus sources could not inhibit 100% of mycelial growth by any mechanism of action. Thus, the clove, thyme, and Eucalyptus citriodora EO’s are promising for developing new ecologically correct products for controlling phytopathogens in citrus fruits.

Non-contact identification of essential oils with IR sensors and analysis of components with an electronic nose

AbstractIn this study, the odour values of rosemary, mint, black cumin, lavender, and thyme oils were determined by an electronic nose working with an Arduino microprocessor. The components of the plants were compared with the sensor data, and the most sensitive sensors were determined by sorting according to the highest components. The study data indicated that the MQ3 sensor exhibited the highest sensitivity for thyme, black cumin, and lavender oils, which contain 63% carvacrol, 38% thymoquinone, and 36% linalool, respectively. Also, MQ7 was the most sensitive sensor for menthone (68%) in mint oil and eucalyptol (45%) in rosemary oil. In addition, a low-cost and non-contact device that works with an infrared sensor has been developed to detect the identity of the oil added into the vial. The study data showed that low-cost Arduino-based IR and odour sensors can determine the identity and component percentage of oils. The fact that the developed device can detect with 100 percent accuracy even in case of peppermint and rosemary oils, which are very similar in appearance, shows that the study data will be an inspiration for contactless determination of oil quality and type.